Analysis of fatal and non-fatal highway crashes in several states for 1969-70 has shown that non-drinking crashes were most numerous at age 18 or 19, whereas drinking crashes did not reach their peak age until 22 or 23. It would appear that young drivers require at least two years to learn how to drive safely without drinking, and at least two more years beyound the legal drinking age of 21 to learn how to drive safely after drinking. On 1 January 1972 the State of Michigan legalized drinking at age 18, along with granting other adult rights and responsibilities. To take advantage of this natural experiment, it is proposed to examine accident files on Michigan fatalities for 1972 and 1973 (and non-fatal crashes if available), and to compare the shape and magnitude of age curves with those previously examined. It is expected that the peak age of drinking crashes for young drivers will decline, thus raising the total crash rate at ages 18-20, but it remains to be seen whether the total crash rate under age 35 will increase, remain stable, or decline. The results will be relevant to several other states which are considering a similar action. It is also proposed, on a longitudinal study of 2800 drivers for which two technical reports are now in preparation, to complete two more volumes concerning time-linked relationships between life events and driving infractions, changes in drinking in relation to changes in driving, and connections between results from the accident file analyses and the longitudinal study.